Check valve



United States Patent [1 3,542,061 [72] Inventor Kllman Korrnos [56] References Cited NONI! scilllile, Rhode Island UNITED s1- A S PATENTS Q J- 1 2 213,1'18' 3/1879 Locke 137/496 5;; l 1970 3,297,260 1/1967 Barlow l37/496X [7 Assignee Gene". signal corpora... 3,392,760 7/ 1968 Soberski I 137/496 a corporation of New York F PATENTS 56,956 4/1944 Netherlands l37/496 [54] CHECK VALVE Primary Exa miner M. Cary Nelson Assistant Examiner R. B. Rothman Attorney- Barlow '& Barlow Conventional diaphragm check valves which comprise broadly a plug supported by a diaphragm have been in use for some time. The function of the, check' valve is toprevent leakage of some fluid or gas when the back pressure; on the downstream side of the valve rises above a predetermined limit. There are occasions when the back pressure exceeds the normal design load for the diaphragm in use, and accordingly the diaphragm will rupture. In the past it has been customary to increase the thickness and/or strength of the diaphragm to effectively design against such an occurrence. but this is not totally satisfactory as the sensitivity of the check valve is impaired. i

SUMMARY OF THE INVENTION A check valve having a body with a chamber therein has a plug member mounted within the chamber; by virtue 'of a diaphragm which permits the plug to reciprocate from a valve closed position to a valve open position depending upon the relative pressures between the upstream and downstream ports that connect to the chamber. The diaphragm that mountsthe plug may be' made of extremely thin material to allow for great sensitivity, and the thin diaphragm material is" protected against rupture from high back pressures by the provision of an overlying annular portion on the plug with a sealing means which will engage the diaphragm-and force the same against the shelf provided within the chamber. This construction then does not allow any unsupported portion of the diaphragm to be exposedt'o large back pressures.

BRIEF oEsc rr oN OF'THE DRAWiNGS FlG. 1 is a sectional view of the valve with the part shown in position when the valve is closed; and FlG.2 is a similar sectional view of the valve with the valve ope-n oEscmPrroN-or-TH PREFERRED EMBODIMENT With reference to the drawings, there. is provided a body for V the check valve consisting of an upper portion 10 and a lower portion 11 which body halves are joined together and held in assembled relationship by through bolts 12, at least three of which are provided and which are spacedabout the periphery Passingthrough the body part 10 and into the recess 14 is an opening or port 17 which serves as an outlet, and passing through the body member 11 is a similar port 18 which serves as an inlet port and which communicates with the recess 15. Mounted within the area known as an annular chamber that is formed by the recesses 14 and l'is a valve pluggenerally designated20 which is made up of two sections, there being an inner section 21 having a conduit 22 therethrough, and this section 21 is madeup effectively of a head 23 with a stem 24 which is ithreaded as at 25. A counterbore 26 in the conduit area 22 is provided, and the remaining portion of the plug is made up of an upper portion 27 which is threadingly received on the threads 25 and which has a lower face 28 that is grooved to receive an .O-ring 30. A diaphragm 32 is received betweenthe two portions of the valve plug and is clamped thereby,-This diaphragm is also received between the two parts 10 and 11 of the body member to be clamped thereby. The lower face of the head 23 of the valve plug portion 21 has -an' O-ring 34 that is received about the conduit opening 22,

and this0-ring is adapted to engage the surface 158 of the recess l5'to-close the conduit 22 from communication with the port 18 to normally urge the valve plug downwardly against the surface B. A spring 36 is received in the counterbore 26 and abuts the upper surface 14A of the recess 14. The valve in operation is shown in P16. 2 with a flow normally occurring from the port 18 through the conduit 22 and thence out the outlet port 1.7. In this condition of operation the pressure at the inlet port 18 is greater-than that at the outlet portion 17 so that, in effect, it can be said that as long as the absolute pressures at.the inlet 18 and the outlet l7 are such that the inlet .pressure is greater than the outlet pressure and that the difference exceeds the closing effect of the spring 36, the valve will remain in the position of FIG. 2. Under some conditions of operation, however, an abnormal condition may exist diaphragm which might at which time an excessive pressure will be present at the outlet 17 which is not overbalanced by an excessive pressure at the inlet 18. When this occurs, the valve plug will be forced downwardly-as viewed in the drawing very tightly.

Reference. should now be had to FIG. 1 where it will be noted that wherrthe valve plug is forced downwardly with an excessive pressure condition at the outlet, the O-ring 34 will prevent any backflow through the valve, and the 0-ring 30 will be pressed tightly against the diaphragm 32, preventing any flow from the outlet from leaking by and exerting itself against the unsupported portion of the diaphragm that exists between the edge of the surface 16 and the recess 15. This condition thereby protects the unsupported inner section of the otherwise rupture by the excessive back pressure. i

It is sometimes desirable to prevent any creeping of the diaphragm 32, and to this end serrations such as shown at 40 on the shelf 16 may be provided, which serrations-are quite normal in the gripping portion of a'diaphragm and, of course, are carried outwardly to the outer edge of the body member where the diaphragm 32 is gripped between the parts 10 and 11. Under all conditions the grooves 40 are not necessary, but they are desirable particularly at the mating portion of the two parts.

I claim:

l. A check valve comprising a valve body member, an annular chamber in said body member, said chamber having an an nular shelf, a cylindrical valve plug, a diaphragm, said valve plug mounted in "said chamber by said diaphragm, the peripheralportion of said diaphragm normally lying on said shelf, said plug having an annular portion overlying said shelf,

said portion having a continuous circular seal means for engaging said diaphragm, said plughaving a conduit therethrough, means cooperating with one end of said conduit to seal the conduit, inlet and outlet ports opening into said chamber at either side of said diaphragm, and means to nor v mally urge said plug in a direction to seal said conduit.'

2. A check valve as in claim l'wherein said diaphragm is gripped by said plug Between opposed surfaces at' least one of which is roughened. i

3. A check valve as in claim 1 wherein said annular shelf surface is roughened. 

